How to search through multiple Blender files to find a specific object?
Use blendfile.py

Using the blendfile script outlined in answers to Is there a way to acces external .blend file&#39;s data with python script? to quickly read blend file and  run thru objects in a blend file without having to open it with blender. 

Here is a simple demo script which prints out file name and a list of objects within that file.I've simply dumped the blendfile.py and script below as blendobjects.py in a root search folder. (rather than using sys.argv etc.. might get back to it)

# install as module or put in same folder.
import blendfile
from pathlib import Path

def get_id_name(block):
    name = block[b'id', b'name'].decode()
    return name[2:]

for file_path in Path('.').glob('**/*.blend'):
    bf = blendfile.open_blend(file_path)
    objects = bf.find_blocks_from_code(b'OB')
    print(file_path, [get_id_name(o) for o in objects])
    bf.close()


result (run in system console not blender), prints blend file name and a list of objects in that file, which can be redirected into a file and searched.

batfinger@shitbox2:~/Documents/blender$ python ./blendobjects.py 
MS2Props02.blend ['Camera', 'Mesh_0449', 'Mesh_0449.001', 'Mesh_0484', 'Mesh_0484.001', 'Mesh_0490', 'Mesh_0490.001', 'Mesh_0773', 'Mesh_0773.001']
yawpitchroll.blend ['Camera', 'Cube', 'Empty', 'Lamp', 'Suzanne']
tests/snoff.blend ['Camera', 'Cube', 'Lamp']
tests/aubio_tests.blend ['Camera', 'Cube', 'Cylinder', 'Lamp']
tests/untitled.blend ['Camera', 'Grid', 'Lamp']
tests/belt.blend ['Armature', 'Armature.001', 'Camera', 'Cone', 'Empty', 'Empty.001', 'Empty.002', 'Empty.003', 'Lamp', 'Torus']